This invention is in the field of sewing machines; more particularly, it is concerned with a presser lifter device for a sewing machine.
In industrial stitching, it frequently is necessary for a sewing machine operator to reposition a work fabric preparatory to initiating a line of stitching. In order to effect this repositioning, the sewing machine operator must elevate the presser foot away from the work fabric, reposition the work fabric and then lower the presser foot onto the work fabric in order to observe if the work fabric has been moved to the proper position. One of the difficulties encountered in the prior art devices using pneumatic or electrical presser foot elevating devices, is that repositioning might be required several times before the proper position is achieved, because the guide to the proper positioning, the presser foot, is elevated to its maximum lift, a position which is inappropriate for its guide function.
Also, in certain sewing applications, it is necessary that the presser foot be slightly elevated during most of the stitching cycle. Thus, to apply decorative stitching to a work fabric it is necessary to elevate the presser foot sufficiently to allow for ready repositioning of the work fabric during the stitching cycle. Since the slight elevation of the presser foot may be necessary for long periods of time, it is also desirable that a minimum amount of effort is required by the operator.
What is required is a presser device having a small, readily achievable presser lift for repositioning of a work fabric beneath the presser foot in addition to the capability of elevating the presser foot to its maximum extent with the least additional motion by the sewing operator so as to provide for least interference with other functions performed by the operator. Ideally, the minimum lift for repositioning is achieved with a minimum effort so as to enable a sewing operator to maintain this lift for long periods of time.